The present invention relates to wind energy systems and fluid working machines. Specifically, the present invention relates to a wind energy system with a fluid working machine acting as a transmission.
Wind energy systems are experiencing an increasing demand. Therefore, large multi-megawatt wind turbines are being installed in many locations throughout the world. They change the kinetic energy of the wind to electrical energy. For large wind energy systems, a transmission box is inevitable in the majority of cases as a result of the high loads that arise from the energy entered from the rotor. However, the construction of the transmission box causes problems as many load changes take place due to the fact that the energy from the wind frequently varies. Therefore, the requirements for the transmission box are numerous and strict.
It is known in the art to use a gearbox as transmission box. In the early phase of wind energy systems, the gearbox was the source of failures and defects in many wind turbines. The reason for these gearbox problems was the difficulty of a correct dimensioning of the gearbox with regard to the load spectrum. Today, the early phase problems have been largely solved, but the construction of the gearboxes is still a difficult task considering size, mass and costs.